Heterogeneous catalysis and photocatalysis

A catalyst is a material that promotes a certain desired chemical reaction without undergoing a net reaction itself. This is achieved by the catalyst enabling a chemical reaction to proceed along an alternative path that has a lower activation energy than without the catalyst present. The enormous impact of catalysis on society can be illustrated by the fact that about 90% of all commercially produced chemical products in a multi-billion dollar market involve the use of catalysts at some stage of their manufacturing process. A particularly important subtopic is heterogeneous catalysis involving gas/solid or liquid/solid interactions and their interfaces. Linked to this research we are also doing research on functional materials for photocatalysis, i.e. the use of (visible) light for directing chemical reactions.

Traditionally, surface sensitive techniques at ultrahigh vacuum conditions have been used and developed to study and understand the physics and chemistry of catalysts. More recently, x-ray absorption spectroscopy (XAS) and high energy x-ray photoelectron spectroscopy (HAXPES) has been applied for in situ characterization at elevated (yet non-operando) pressure conditions, still leaving a pressure gap to realistic conditions.

Closing the pressure gap

Recently, RIXS has been added to the arsenal of x-ray techniques. RIXS excels particularly at operando studies that involve ambient conditions, which are out of the reach of ordinary electron spectroscopies. RIXS can close this pressure gap, a longstanding issue in the field of heterogeneous catalysis. Two examples of recent studies are (i) ethylene epoxidation over silver where subsurface oxygen species were identified and (ii) in situ formed Co-based catalyst systems for catalytic water splitting. The first study was performed under operando conditions at 1 bar pressure and up to 250° C.

People

Laurent Duda (Docent)
Felix Massel (PhD student)
Bertrand Philippe (Researcher)
Håkan Rensmo (Professor)
Anders Sandell (Professor)

Selected publications:

Reaction cell for in situ soft x-ray absorption spectroscopy and resonant inelastic x-ray scattering measurements of heterogeneous catalysis up to 1 atm and 250° C
Paw Toldbad Kristiansen, TCR Rocha, Axel Knop-Gericke, J.H. Guo, Laurent-C. Duda.
Review of Scientific Instruments, 2013, 84, 113107.

Transition metal doping effects in Co-phosphate catalysts for water splitting studied with XAS
F. Massel, S. Ahmadi, M. Hahlin, Y.S. Liu, J.H. Guo, T. Edvinsson, H. Rensmo, L.-C. Duda.
Journal of Electron Spectroscopy and Related Phenomena.

Nickel-vanadium monolayer double hydroxide for efficient electrochemical water oxidation​
Fan K; Chen H; Ji YF; Huang H; Claesson PM; Daniel Q; Philippe B; Rensmo H; Li FS; Luo Y; Sun LC.
Nat Commun. 2016;7:9.

In-Situ Probing of H2O Effects on a Ru-Complex Adsorbed on TiO2 Using Ambient Pressure Photoelectron Spectroscopy
Eriksson SK; Hahlin M; Axnanda S; Crumlin E; Wilks R; Odelius M; Eriksson AIK; Liu Z; Åhlund J; Hagfeldt A; Starr DE; Bär M; Rensmo H; Siegbahn H.
Top Catal. 2016;59(5-7):583-90.

Photochemistry of Carboxylate on TiO2(110) Studied with Synchrotron Radiation Photoelectron Spectroscopy
A. Sandell, D. Ragazzon, A. Schaefer, M. H. Farstad, A. Borg.
Langmuir 32, 11456 (2016).

Master and Bachelor projects

We invite students interested in master and bachelor projects. For more details about available projects, please contact Laurent Duda.